Control system



E. AUSTIN CONTROL SYSTEM June 11, 1929.

Filed Feb. 2, 1925 mfzf ln lllllll l i- Im/entor Edward- Austin y W WHis Attorney.

Patented June 11, 1929.

UNITED STATES PATENT OFFICE.

EDWARD AUSTIN, OF SCHENECTADY, NEW YORK; ASSIGNOR T GENERAL ELECTRICCOMPANY, A CORPORATION OF NEW YORK.

CONTROL SYSTEM.

Application filed February 2, 1923. Serial No. 616,630.

. My present invention relates to systems for controlling the operationof electrically actuated devices, and more particularly to systems inwhich the operation of such devices is controlled by means of currentstransmitted to the devices from a distant point. I

One of the objects of my invention isto provide a simple and efficientmeans for actuating an electrical device or devices from a distant pointby means of currents of such characteristics that a desired device ordevices may be actuated without operating other devices which may beconnected to the distribution system over which the controlling currentsare transmitted.

A further object of my invention is to provide a device which may beactuated by a current having a given characteristic such as apredetermined frequency and which will not be actuated by currentshaving different characteristics.

Still another object of my invention is to provide a means fortransmitting control currents over a distribution system which isemployed for other purposes than the transmission of control currentsand which is so arranged that the operation of the controlled means willbe independent of currents which may be transmitted over thedistribution system for other purposes.

The novel features which I believe to be characteristic of my inventionare set forth with particularity in the appended claims.

My invention itself, however both as to its organization and method ofoperation will best bGJlIldGIStOOd b reference to thefollowingdescription ta en in connection with the accompanying drawing in which Ihave indicated diagrammatically one way whereby my invention may becarried into effect. I have shown in the drawing a distribution 7 systemcomprising conductors 1 which may be supplied with current from thesecondary windings 2 of a three-phase Y connected transformer withgrounded neutral. The currents supplied to this distribution system maybe employed for the operation of any electrical apparatus desired. Ihave indicated at a distant point from the supply station a lightingcircuit comprising lamps 3 sup lied with current from one phase of theistribution system through a transformer 4. In order to illustrate theoperation of my invention I have indicated a means whereby this lightingcircuit may be opened and closed from the supply station withoutinterfering with the operation of any other consumption devices whichmay be connected to the distribution system.

The control means for the lighting circuit which I have indicatedcomprises at the supply station an electron discharge device 5 which maybe employed to produce currents of any desired frequency. Current forthe operation of the device 5 is obtained from the distributionconductors through a transformer 6, the secondary winding of which isconnected to the primary windings 7 of a second transformer through apush botton switch 8. Current for heating the filamentary cathode 9 ofthe electron discharge device 5 is obtained from a secondary winding 10which is associated with the primary winding 7. Current for the platecircuit of the device 5 is obtained from a secondary winding 11 which isassociated with primary winding 7. The primary 12 of an oscillationtransformer is connected to the plate electrode 13 of device 5 through acondenser 14 and to the grid through a grid condenser 15 and grid leak16. The mid point 17 of the secondary 10 is grounded at 18 and one pointin the primary 12 of the oscillation transformer is also grounded at 18through an adjustable tap 19. A second point in the primary 12 is alsoconnected to ground at 18 through an adjustable tap 20 and a bypasscondenser 21.

The secondary 22 of the oscillation transformer is connected to onephase of the distribution system through a switch 23 and a condenser 24of such capacity as to prevent any appreciable flow of current from thedistribution system through the secondary winding 22 ofthe oscillationtransformer. By proper tuning of the oscillating system throughadjustment of the taps 19 and 20 or adjustment of the condenser 21 it ispossible to impress upon the distribution system currents of anyfrequency desired whenever the push button switch 8 is operated.

At or near the point where the switch 25 is located which controls thecircuit of lamps 3, I provide two relays 26 and 27 which are arranged torespond only to currents of a are included in a control circuit forswitch 25. Contacts 30 and 31 of relay 26, are also included in thecontrol circuit of switch 25.

I have indicated these contacts as open so that the control circuit ofswitch 25 is open, the switch is also open and the lamps 3 are notlighted.

vWhen it is desired to close switch25 so as to close the circuit oflamps 3, a current is impressed upon the mains 1 of a predeterminedfrequency for which the circuit made up of condenser 32 and variometer33 is resonant. As a result current is supplied from variometer 33 tothe secondary coil 34 and the circuit in which coil 34 is included. Thecircuit is madeup of a series condenser 35 and series inductance 36 andinductance 37, which is in shunt to condenser 38. Inductances 36 and 37serve as actuating coils for relay 26 and capacity 35 and inductances 34and 36 form a series resonant circuit for the frequency impressed on thecircuit while capacity 38 and inductance 37 form a parallel resonantcircuit for the frequency impressed thereon. As a result the currentsflowing in coils 36 and 37 will differ in phase and hence be capable ofefficiently actuating relay 26 and closing contacts 30 and 31. Thecontrol circuit of switch 25 also includes a holding coil 39 for relay26, which holds contacts 30 and 31 together after .relay 26 has beenactuated.

When it is desired to extinguish lamps 3 a frequency for which thecircuit made up of capacity 40 and variometer 41 is resonant.

This supplies current to the actuating circuit of relay 27, which ismade up in the same manner as that of relay 26. By the actuation ofrelay 27 contacts 28 and 29 are separated thus opening the controlcircuit of switch 25 and the switch is opened. 'At the same time holdingcoil 39 is deenergized, permitting contacts 30 and 31 to open. As aresult relay 26 is again in condition to close the control circuit ofswitch 25.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is:

1; The combination in a control system of an electrical supply circuitadapted to be supplied with currents of different desired frequencies,resonant circuits connected to said supply circuit for receivingtherefrom currents of desired frequencies and additional resonantcircuits associated with said first mentioned resonant circuits foroperating electrical apparatus each of'said second mentioned. resonantcircuits comprising a coil which is tuned with a series capacity and acoil which is tuned with a shunt capacity. i

coils, a' common series resonant circuit for supplying to all of saidrelay coils currents of a predetermined frequency for the actuation ofsaid relay and means for supplying to different actuating coils of saidrelay from said resonant circuit currents of different phase. I

3. The combination in a control system of an electrical supply circuitadapted to be supplied with currents of different desired frequencies,resonant circuits connected to said supply circuit for receivingtherefrom currents of desired frequencies, relays havin a plurality ofactuating coils adapted to e supplied with current from said resonantcircuits, and additional means for simultaneously supplying to differentactuating coils of each relay from a corresponding resonant circuitcurrents of different phase.

4. In combination, a circuit to be controlled, said circuit including aswitch biased to open position and a switch biased to closed position,means responsive to current of a certain frequency for closing saidfirst mentioned switch, means for maintaining said switch in closedposition, means responsive to current of another frequency for openingthe second mentioned switch and resonant circuits adapted to supply saidfrequency responsive means with currents of desired frequencies.

5. The combination, in .a control system, of a plurality of circuitsresonant to current of different frequencies, additional resonantcircuits associated with the first mentioned circuits for operatingelectrical apparatus, each of said, second mentioned resonant circuitscomprising a coil which is tuned with a series capacity and a coil whichis tuned with a shunt capacity and electrical apparatus operated by saidcoils. v

6. he combination, in a control system, of a plurality of circuitsresonant to current of certain frequencies, relays having a plurality ofactuating coils adapted to be supplied with current from said resonantcir cuits, and additional means whereby currents of different phase maybe simultaneously supplied to the different actuating desiredfrequencies, relays having a plural-F ity of actuating coils, additionalresonant circuits associated with said first resonant circuits andincluding said actuating coils and means associated with said additionalresonant circuit for supplyingto different actuating coils of each relaycurrents of different phase.

8. The combination in a control system of a relay having two actuatingcoils connected and means for supplying to said common cirin a commoncircuit including a series concuit currents of said certain frequency todenser and resonant at a certain frequency, produce actuation of saidrelay.

a second condenser connected in parallel In Witness whereof I havehereunto set my 5 with one of said coils and so pro ortioned hand, this31st day of January, 1923.

with respect to said coil as to pro uce resonance therewith at saidcertain frequency,

EDWARD AUSTIN.

